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| author |  Liu Ying <victor.liu@nxp.com>
| 2022-01-24 10:40:07 +0800 |
|---|---|---|
| committer |  Vinod Koul <vkoul@kernel.org>
| 2022-02-02 10:33:04 +0530 |
| commit | 9a8406ba1a9a2965c27e0db1d7753471d12ee9ff (patch) | |
| tree | 2fceeab99e34a3b57eb2f930866ff402ea2fa372 /drivers/phy/rockchip | |
| parent | phy: phy-mtk-tphy: Fix duplicated argument in phy-mtk-tphy (diff) | |
| download | linux-9a8406ba1a9a2965c27e0db1d7753471d12ee9ff.tar.gz linux-9a8406ba1a9a2965c27e0db1d7753471d12ee9ff.tar.bz2 linux-9a8406ba1a9a2965c27e0db1d7753471d12ee9ff.zip | |
phy: dphy: Correct clk_pre parameter
The D-PHY specification (v1.2) explicitly mentions that the T-CLK-PRE
parameter's unit is Unit Interval(UI) and the minimum value is 8. Also,
kernel doc of the 'clk_pre' member of struct phy_configure_opts_mipi_dphy
mentions that it should be in UI. However, the dphy core driver wrongly
sets 'clk_pre' to 8000, which seems to hint that it's in picoseconds.
So, let's fix the dphy core driver to correctly reflect the T-CLK-PRE
parameter's minimum value according to the D-PHY specification.
I'm assuming that all impacted custom drivers shall program values in
TxByteClkHS cycles into hardware for the T-CLK-PRE parameter. The D-PHY
specification mentions that the frequency of TxByteClkHS is exactly 1/8
the High-Speed(HS) bit rate(each HS bit consumes one UI). So, relevant
custom driver code is changed to program those values as
DIV_ROUND_UP(cfg->clk_pre, BITS_PER_BYTE), then.
Note that I've only tested the patch with RM67191 DSI panel on i.MX8mq EVK.
Help is needed to test with other i.MX8mq, Meson and Rockchip platforms,
as I don't have the hardwares.
Fixes: 2ed869990e14 ("phy: Add MIPI D-PHY configuration options")
Tested-by: Liu Ying <victor.liu@nxp.com> # RM67191 DSI panel on i.MX8mq EVK
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> # for phy-meson-axg-mipi-dphy.c
Tested-by: Neil Armstrong <narmstrong@baylibre.com> # for phy-meson-axg-mipi-dphy.c
Tested-by: Guido Günther <agx@sigxcpu.org> # Librem 5 (imx8mq) with it's rather picky panel
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Link: https://lore.kernel.org/r/20220124024007.1465018-1-victor.liu@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/phy/rockchip')
| -rw-r--r-- | drivers/phy/rockchip/phy-rockchip-inno-dsidphy.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/phy/rockchip/phy-rockchip-inno-dsidphy.c b/drivers/phy/rockchip/phy-rockchip-inno-dsidphy.c index 347dc79a18c1..630e01b5c19b 100644 --- a/drivers/phy/rockchip/phy-rockchip-inno-dsidphy.c +++ b/drivers/phy/rockchip/phy-rockchip-inno-dsidphy.c @@ -5,6 +5,7 @@ * Author: Wyon Bi <bivvy.bi@rock-chips.com> */ +#include <linux/bits.h> #include <linux/kernel.h> #include <linux/clk.h> #include <linux/iopoll.h> @@ -364,7 +365,7 @@ static void inno_dsidphy_mipi_mode_enable(struct inno_dsidphy *inno) * The value of counter for HS Tclk-pre * Tclk-pre = Tpin_txbyteclkhs * value */ - clk_pre = DIV_ROUND_UP(cfg->clk_pre, t_txbyteclkhs); + clk_pre = DIV_ROUND_UP(cfg->clk_pre, BITS_PER_BYTE); /* * The value of counter for HS Tlpx Time |